Exposed

Distribution by Scientific Domains
Distribution within Medical Sciences

Terms modified by Exposed

  • exposed animals
  • exposed area
  • exposed bone
  • exposed case
  • exposed cell
  • exposed child
  • exposed group
  • exposed groups
  • exposed individual
  • exposed infant
  • exposed mouse
  • exposed part
  • exposed patient
  • exposed population
  • exposed pulp
  • exposed rat
  • exposed root surface
  • exposed site
  • exposed skin
  • exposed subject
  • exposed surface
  • exposed worker

  • Selected Abstracts


    Population-based Triage Management in Response to Surge-capacity Requirements during a Large-scale Bioevent Disaster

    ACADEMIC EMERGENCY MEDICINE, Issue 11 2006
    Frederick M. Burkle Jr MD
    Both the naturally occurring and deliberate release of a biological agent in a population can bring catastrophic consequences. Although these bioevents have similarities with other disasters, there also are major differences, especially in the approach to triage management of surge capacity resources. Conventional mass-casualty events use uniform methods for triage on the basis of severity of presentation and do not consider exposure, duration, or infectiousness, thereby impeding control of transmission and delaying recognition of victims requiring immediate care. Bioevent triage management must be population based, with the goal of preventing secondary transmission, beginning at the point of contact, to control the epidemic outbreak. Whatever triage system is used, it must first recognize the requirements of those Susceptible but not exposed, those Exposed but not yet infectious, those Infectious, those Removed by death or recovery, and those protected by Vaccination or prophylactic medication (SEIRV methodology). Everyone in the population falls into one of these five categories. This article addresses a population approach to SEIRV-based triage in which decision making falls under a two-phase system with specific measures of effectiveness to increase likelihood of medical success, epidemic control, and conservation of scarce resources. [source]


    Vascular endothelial growth factor in edematous mouse embryos induced by retinoic acid in utero

    CONGENITAL ANOMALIES, Issue 2 2001
    Yoshiko Yasuda
    ABSTRACT, Vascular endothelial growth factor (VEGF) is induced by hypoxic environment and contributes to vascular formation in both developing embryos and adults. Exogenous retinoic acid (RA) induces avascular yolk sacs with anemic stunted embryos of day 9 and 10 of gestation when RA is given to pregnant mice on day 6, 6.5 or 7 of pregnancy (Yasuda et al., 1996). We undertook the present studies to find out whether VEGF is activated and plays any role in those RA-exposed embryos. Embryos were obtained from dams given 60 mg/kg of RA on day 6 or 7 of pregnancy and sacrificed three days later. Most RA-exposed embryos showed edematous swelling without prominent vascular nets, but had beating heart tubes on day 9 and day 10 of gestation. Microscopic examination of developing tissue components showed various degrees of degeneration, and distension of the dorsal aorta when the body cavity was dosed. Northern blot analysis revealed expression of VEGF mRNA in the RA-exposed and control embryos. The highest expression of VEGF mRNA was seen in the embryos of day 10 exposed to RA on day 7, and these embryos had a significantly lower ATP content than did the controls (p < 0.01). Immunoreactive VEGF was detectable in both experimental and control embryos; in the former it was especially visible in the distended neuroepithelium, endothelium and membranes. These VEGF-immunoreactive regions also expressed another permeability factor, bradykinin. These findings suggest that VEGF upregulated by hypoxic conditions in edematous embryos induced by RA exposure in utero acts as hyperpermeability. [source]


    Pulp capping with adhesive resin-based composite vs. calcium hydroxide: a review

    DENTAL TRAUMATOLOGY, Issue 6 2000
    A. H. B. Schuurs
    Abstract , The results of some short-term experiments suggest that direct capping of a vital pulp with the modern resin-based composite systems may be as effective as capping with calcium hydroxide. Total cavity etching with 10% phosphoric acid seems to be safe for the exposed pulp, but unless annulled by calcium hydroxide 35% phosphoric acid may be disastrous. For hemostasis and cleaning of the pulp wound both sodium hypochlorite and saline seem suitable, whereas the effectiveness of a 2% chlorhexidine solution is questionable. Although hard-setting calcium hydroxide cements may induce the formation of dentin bridges, they appear not to provide an effective long-term seal against bacterial factors. Within a few years, the majority of mechanically exposed and capped pulps show infection and necrosis due to microleakage of such capping materials and tunnel defects in the dentin bridges. It is unknown whether newer types of resin containing calcium-hydroxide-products will act as a permanent barrier. The cytotoxicity of the resin-based composites and the temperature rise during polymerisation may not be of concern, but microleakage, sensitisation and allergic reactions may pose problems. Based on available data, pulp capping with resin-based composites may be said to be promising, but more and long-term research is mandatory before the method can be recommended. [source]


    Prenatal and family risks of children born to mothers with epilepsy: effects on cognitive development

    DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 2 2008
    Karl Titze PhD
    The offspring of mothers with epilepsy are considered to be at developmental risk during pregnancy from: (1) generalized maternal seizures (hypoxia); (2) teratogenicity of antiepileptic drugs (AEDs); and (3) adverse socio-familial conditions associated with having a chronically sick mother. Sixty-seven children of mothers with epilepsy and 49 children from non-affected mothers, matched for control variables, were followed from birth to adolescence (53 males, 63 females; mean age 14y 2mo, range 10-20y). Prediction of intellectual performance of these children during adolescence was calculated from the following variables: maternal generalized seizures, prenatal exposure to AEDs, and quality of family stimulation (HOME Inventory) assessed in children at 2 years of age. Children who were prenatally exposed to AEDs achieved lower IQs than control children at adolescence. This effect was moderately significant for children who had been exposed to monotherapy (6 IQ points lower), but was considerable in those exposed to polytherapy (12 IQ points lower). Generalized seizures during pregnancy, observed in half the mothers, did not exacerbate this effect. Relative to prenatal risk status, the quality of the family environment had varied effects on intellectual development. Children with prenatal risks appeared to be more vulnerable to environmental disadvantage than control children, but they also showed longer-lasting effects of environmental support. [source]


    Similar and functionally typical kinematic reaching parameters in 7- and 15-month-old in utero cocaine-exposed and unexposed infants

    DEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2004
    E. Z. Tronick
    Abstract This study examined the effects of intrauterine cocaine exposure on the reaches of 19 exposed and 15 unexposed infants at 7 and 15 months using kinematic measures. Infants sat at a table and reached for a rattle, a toy doll, and a chair. Videotaped reaches were digitized using the Peak Performance system. Kinematic movement variables were extracted (e.g., reach duration, peak velocity, movement units, path length) and ratios computed (e.g., path length divided by number of movement units). Regardless of exposure status, reaches of older infants were faster, more direct, had fewer movement units, and covered more distance with the first movement unit. Exposed infants covered more distance per movement unit than unexposed infants, but there were no other significant differences. Reaches of exposed and unexposed infants were essentially similar. Importantly, reach parameters for these high-risk infants were similar to reach parameters for infants at lower social and biological risk. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 168,175, 2004. [source]


    Classical conditioning in the rat fetus: Temporal characteristics and behavioral correlates of the conditioned response

    DEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2002
    William P. Smotherman
    Abstract This study examined the temporal characteristics and behavioral correlates of the conditioned response (CR) following classical conditioning of the embryonic Day 20 (E20 rat fetus). The conditioning procedure involved pairing of an artificial nipple (the CS) with an infusion of milk (the US) to establish classical conditioning. The test for classical conditioning involved measurement of a stimulus-evoked facial wiping response in a classical conditioning test. Experiment 1 compared the effectiveness of one- and three-trial procedures to establish classical conditioning. Experiment 2, 3, and 4 described the time course for the CR following one- and three-trial conditioning procedures. Experiments 3b and 4b describe the behavioral responses to (a) presentation of the CS at the time of conditioning, (b) infusion of the milk US at the time of conditioning, and (c) reexposure to the CS before the test for classical conditioning. Experiments 5 and 6 exposed the fetus to manipulations that either increased or decreased stretching (a behavior found to be associated with the CR). The results are discussed in terms of the temporal characteristics and behavioral correlates of conditioned and unconditioned responses and their mediation by activity in endogenous mu and kappa opioid systems. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 40: 116,130, 2002. DOI 10.1002/dev.10017 [source]


    Thrips see red , flower colour and the host relationships of a polyphagous anthophilic thrips

    ECOLOGICAL ENTOMOLOGY, Issue 5 2007
    A. YAKU
    Abstract 1.,The common blossom thrips, Frankliniella schultzei, is a polyphagous anthophilic species that colonises a wide range of host-plant species across different plant taxa. The environmental cues used by these polyphagous insects to recognise and locate host plants are not known. We therefore determined if colour is an important environmental signal used by F. schultzei to recognise flowers of eight of its more significant host-plant species. 2.,The effect of flower colour on the colonisation of different host plant species by F. schultzei was investigated by collecting and analysing the following: (a) numbers of thrips from different heights and aspects of the primary host plant Malvaviscus arboreus, (b) thrips distribution within flowers of Hibiscus rosasinensis, (c) colour reflectance from flowers of eight different host-plant species, and (d) reflectance from different coloured sticky traps and the number of thrips trapped on them at different times of the day and on different dates. 3.,The results indicate that: (a) the thrips (both sexes) concentrate towards the top of the primary host plant M. arboreus and are not distributed differentially according to sunny or shady aspect of the plant, (b) the number of female thrips on H. rosasinensis was higher in anthers compared to petals (corolla) and the basal parts of the flower, and males were as numerous on the petals as were females, and (c) there is a common floral reflectance pattern (but with different intensities) across the eight host plant species, mainly in the red part of the spectrum (600,700 nm). 4.,Results of colour sticky trapping show that red attracts more female thrips compared to any other colour and that most were caught between 09.00 and 11.00 hours. By contrast, more male thrips were trapped between 07.00 and 09.00 hours. Males were more evenly distributed across the different colours but the highest numbers were associated with the yellow traps. 5.,The higher densities of thrips at the top of their host plant may be related to the early morning (07.00,11.00 hours) activity of the thrips, when the top portions of the plant are more exposed to sunlight. The sex-related distributions of F. schultzei thrips across time, coloured sticky traps, and various parts of the flowers seem to be related to mating swarm formation by the males, on the one hand, and the relative frequency and intensity of the use of M. arboreus by the females, on the other, as a feeding and oviposition site. Frankliniella schultzei females respond more strongly to red than to any other colours, so it is predicted that the spectral properties of colour recognition by this species will correlate with the predominant red reflectance of its primary host, M. arboreus, and that there may well be a sex-related difference in colour recognition within this species. [source]


    Trends in and predictors of second-hand smoke exposure indexed by cotinine in children in England from 1996 to 2006

    ADDICTION, Issue 3 2010
    Michelle Sims
    ABSTRACT Aims To explore trends in and predictors of second-hand smoke (SHS) exposure in children. To identify whether inequalities in SHS exposure are changing over time. Design Repeated cross-sectional study with data from eight annual surveys conducted over an 11-year period from 1996 to 2006. Setting England. Participants Nationally representative samples of children aged 4,15 years living in private households. Measurements Saliva cotinine (4,15-year-olds), current smoking status (8,15-year-olds), smoking status of parents and carers, smoking in the home, socio-demographic variables. Findings The most important predictors of SHS exposure were modifiable factors,whether people smoke in the house on most days, whether the parents smoke and whether the children are looked after by carers who smoke. Children from more deprived households were more exposed and this remained the case even after parental smoking status has been controlled for. Exposure over time has fallen markedly among children (59% decline over 11 years in geometric mean cotinine), with the most marked decline observed in the period immediately preceding smoke-free legislation. Declines in exposure have generally been greater in children most exposed at the outset. For example, in children whose parents both smoke, median cotinine declined annually by 0.115 ng/ml compared with 0.019 ng/ml where neither parent smokes (P < 0.05). Conclusions In the 11 years leading up to smoke-free legislation in England, the overall level of SHS exposure in children as well as absolute inequalities in exposure have been declining. Further efforts to encourage parents and carers to quit and to avoid smoking in the home would benefit child health. [source]


    Exposure of children and adolescents to alcohol advertising on Australian metropolitan free-to-air television

    ADDICTION, Issue 7 2009
    Lynda Fielder
    ABSTRACT Aim This study investigated the exposure of underage youth to alcohol television advertising on metropolitan free-to-air television in the five mainland capital city markets of Australia. Design Exposure levels (target audience rating points; TARPs) were obtained for all alcohol advertisements screened from November 2005 to October 2006 in each capital city market for: children 0,12 years; underage teens 13,17 years; young adults 18,24 years; and mature adults 25+ years. The 30 most exposed advertisements across age groups were then content-analysed for elements appealing to children and underage youth. Results In each of the five metropolitan markets, mature adults were most exposed to alcohol advertising. Children were exposed to one-third the level of mature adults and underage teens to approximately the same level as young adults. However, there was considerable variation in media weight between markets, such that underage teens in two markets had higher advertising TARPs than young adults in other markets. All 30 highest exposed advertisements contained at least one element known to appeal to children and underage youth, with 23 containing two or more such elements. Fifteen of the 30 advertisements featured an animal. Conclusions The self-regulation system in Australia does not protect children and youth from exposure to alcohol advertising, much of which contains elements appealing to these groups. [source]


    Cytogenetic status in newborns and their parents in Madrid: The BioMadrid study

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2010
    Virginia Lope
    Abstract Monitoring cytogenetic damage is frequently used to assess population exposure to environmental mutagens. The cytokinesis-block micronucleus assay is one of the most widely used methods employed in these studies. In the present study we used this assay to assess the baseline frequency of micronuclei in a healthy population of father-pregnant woman-newborn trios drawn from two Madrid areas. We also investigated the association between micronucleus frequency and specific socioeconomic, environmental, and demographic factors collected by questionnaire. Mercury, arsenic, lead, and cadmium blood levels were measured by atomic absorption spectrometry. The association between micronucleated cell frequency and the variables collected by questionnaire, as well as, the risk associated with the presence of elevated levels of metals in blood, was estimated using Poisson models, taking the number of micronucleated cells in 1,000 binucleated cells (MNBCs) as the dependent variable. Separate analyses were conducted for the 110 newborns, 136 pregnant women, and 134 fathers in whom micronuclei could be assessed. The mean number of micronucleated cells per 1,000 binucleated cells was 3.9, 6.5, and 6.1 respectively. Our results show a statistically significant correlation in MNBC frequency between fathers and mothers, and between parents and newborns. Elevated blood mercury levels in fathers were associated with significantly higher MNBC frequency, compared with fathers who had normal mercury levels (RR:1.21; 95%CI:1.02,1.43). This last result suggests the need to implement greater control over populations which, by reason of their occupation or life style, are among those most exposed to this metal. Environ. Mol. Mutagen., 2010. © 2009 Wiley-Liss, Inc. [source]


    DNA damage in leukocytes of workers occupationally exposed to arsenic in copper smelters

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2005
    Jadwiga Palus
    Abstract Inorganic arsenic (i-As) is a known human carcinogen; however, humans continue to be exposed to i-As in drinking water and in certain occupational settings. In this study, we used the Comet assay to evaluate DNA damage in the somatic cells of workers from three Polish copper smelters who were occupationally exposed to i-As. Blood samples were collected from 72 male workers and 83 unexposed male controls and used for the detection of DNA damage, oxidative DNA damage, and DNA damage after a 3-hr incubation in culture. Urine samples were collected to assess the level of exposure. The mean concentration of arsenic metabolites in urine [the sum of arsenite (AsIII), arsenate (AsV), monomethylarsenate (MMA) and dimethylarsenate (DMA)] and the concentrations of DMA (the main metabolite in urine) were higher in workers than in controls, but the differences were not statistically significant. By contrast, the level of DNA damage, expressed as the median tail moment, was significantly higher in the leukocytes of workers than in the controls. Comet assays conducted with formamidopyrimidine glycosylase (FPG) digestion to detect oxidative DNA damage indicated that oxidative lesions were present in leukocytes from both the exposed and control groups, but the levels of damage were significantly higher among the workers. Incubation of the cells in culture resulted in a significant reduction in the levels of DNA damage, especially among leukocytes from the workers, suggesting that the DNA damage was subject to repair. Our findings indicate that copper smelter workers have increased levels of DNA damage in somatic cells, suggesting a potential health risk for the workers. Although i-As was present in air samples from the smelters and in urine samples from workers, no clear association could be made between i-As exposure and the DNA damage. Environ. Mol. Mutagen., 2005. © 2005 Wiley-Liss, Inc. [source]


    Cytogenetic damage in female Chilean agricultural workers exposed to mixtures of pesticides

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2005
    Carolina Márquez
    Abstract The VIII Region of Bío-Bío is a major fruit-growing area of Chile that makes intensive use of agricultural pesticides. The cytogenetic damage associated with exposure to mixtures of pesticides was evaluated by comparing peripheral blood lymphocyte micronucleus (MN) frequencies in a group of 64 female agricultural workers and 30 female controls. The exposed subjects worked during the spring and summer in thinning and pruning fruit trees and in harvesting and packing different fruits, such as raspberries, grapes, apples, and kiwis. They did not use any protective measures during their work activities. A significant increase in the frequency of binucleated cells with micronuclei (BNMN) was found in the exposed women as compared with the controls (36.94 ± 14.47 vs. 9.93 ± 6.17 BNMN/1000 BN cells; P < 0.001). The frequency of BNMN varied as a function of age in both the exposed and control groups, but no correlation was found between BNMN frequency and the duration of exposure. Also, smoking and other habits had no effect on MN frequency. Our study confirms that occupational exposure to pesticide mixtures results in cytogenetic damage. Environ. Mol. Mutagen., 2005. © 2004 Wiley-Liss, Inc. [source]


    Aroclor 1254 alters morphology, survival, and gene expression in Xenopus laevis tadpoles

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2002
    Anna M. Jelaso
    Abstract PCBs are persistent environmental contaminants that cause a variety of adverse health effects in wildlife and humans. This article describes the use of signature gene expression patterns that link increased PCB exposure with progressive, adverse biological effects. Developing Xenopus laevis tadpoles of two age classes were exposed to the PCB mixture Aroclor 1254 for 2 days. Real-time PCR was used to quantitate mRNA expression for 11 physiologically relevant, potential bioindicator genes. Younger tadpoles (5 days postfertilization) were resistant to Aroclor 1254 and showed few changes in gross morphology, swimming behavior, survival, or gene expression. Older tadpoles (11 days postfertilization) were more susceptible to Aroclor 1254. Exposure to 25 and 50 ppm Aroclor 1254 caused alterations in gross morphology and swimming behavior and statistically significant decreases in survival. These tadpoles showed statistically significant decreases in gene expression for 9 out of the 11 genes measured. Tadpoles exposed to 10 ppm showed incipient health changes but had gene expression profiles similar to the tadpoles treated with higher doses of Aroclor 1254. Tadpoles exposed to 1 ppm did not exhibit any observable adverse health effects, yet statistically significant decreases in gene expression occurred in these tadpoles (4 out of 11 genes). After prolonged exposure, tadpoles exposed to 1 and 10 ppm Aroclor 1254 exhibited health effects similar to those exposed to higher concentrations. Therefore, changes in expression of specific genes may serve not only as molecular bioindicators of Aroclor 1254 exposure but also as predictors of impending adverse health effects. Environ. Mol. Mutagen. 40:24,35, 2002. © 2002 Wiley-Liss, Inc. [source]


    Attenuating effects of natural organic matter on microcystin toxicity in zebra fish (Danio rerio) embryos,benefits and costs of microcystin detoxication

    ENVIRONMENTAL TOXICOLOGY, Issue 1 2006
    Jimena Cazenave
    Abstract To contribute to the understanding of joined factors in the environment, impact of pure microcystins (-RR and -LF) on zebra fish (Danio rerio) embryos were investigated individually and in combination with a natural organic matter (NOM). The applied NOM was a reverse osmosis isolate from Lake Schwarzer See (i.e., Black Lake, BL-NOM). Teratogenic effects were evaluated through changes in embryonic development within 48 h of exposure. Detoxication activities were assessed by the activities of phase II biotransformation enzymes, soluble and microsomal glutathione S -transferase (s, mGST). Oxidative stress was assessed by determining both the production of hydrogen peroxide and by analyzing the activities of the antioxidative enzymes, guajacol peroxidase (POD), catalase (CAT), glutathione peroxidase (GPx), and the glutathione restoring enzyme glutathione reductase (GR). Energetic costs were evaluated by determining contents of fat, carbohydrates, and proteins in both exposed and control embryos. BL-NOM attenuated toxic effects of MC-LF and MC-RR verified by less pronounced teratological effects within 24 h, in particular, as well as less rise in the activity of s-GST, when compared with embryos exposed to either pure toxins or in combination with organic matter. BL-NOM also diminished oxidative effects caused by MC-LF; however, it failed to attenuate oxidative stress caused by MC-RR. Content of lipids was significantly reduced in exposed embryos following a trend similar to that obtained with teratological and enzymatic assays confirming the attenuating effect of BL-NOM. Physiological responses to microcystins and NOM required energetic costs, which were compensated to the expense of the energy resources of the yolk, which in turn might affect the normal development of embryos. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 22,32, 2006. [source]


    Toxicity of arsenic species to Lemna gibba L. and the influence of phosphate on arsenic bioavailability

    ENVIRONMENTAL TOXICOLOGY, Issue 1 2004
    Martin Mkandawire
    Abstract The toxicity of arsenic (As) species to Lemna gibba L. and the influence of PO on As bioavailability and uptake were tested in batch culture. L. gibba were exposed to six test concentrations of NaHAsO4 · 7H2O and NaAsO3, with 0, 0.0136, 13.6, and 40 mg L,1 KH2PO4. In batch culture As toxicity to L. gibba did not relate linearly to As concentration. The growth rate, related to frond number as recommended by OECD and ISO/DIN, was significantly inhibited in fronds exposed to 20,50 ,g L,1 As(III) compared with fronds exposed to As(V). The growth rate was stimulated when plants were exposed to 50,250 ,g L,1 of both As(III) and As(V). After exposure to 300,800 ,g L,1 growth inhibition was significantly higher for As(III) than for As(V), whereas above 800 ,g L,1 As(V) was inhibited the most. The bioaccumulation of As(III) and As(V) was significantly higher for P-deficient cultures (0.98 ± 0.08 and 1.02 ± 0.19 g kg,1, respectively for 0.0136 mg L,1 PO) than for P-sufficient cultures (243 and 343 mg kg,1 for 40 mg L,1, respectively). Plants exposed to As(V) had uptake and accumulation values slightly higher than did plants exposed to As(III). No significant differences in bioaccumulation were found between plants exposed to a concentration of As(III) >1 mg L,1 and those exposed to As(V) at the same concentration. This indicates a direct relationship to P content in the culture. Toxicity may result from the uptake of As(V) instead of PO as a result of ion competition during uptake because of close thermodynamic properties, which may change the interaction among components in the media. The toxicity pattern is interpreted as a manifestation of changing speciation in the batch culture and of the oxidation of As(III) to As(V) in an oxygen-rich environment. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 26,34, 2004. [source]


    Comparative hepatic activity of xenobiotic-metabolizing enzymes and concentrations of organohalogens and their hydroxylated analogues in captive greenland sledge dogs (Canis familiaris),

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2009
    Jonathan Verreault
    Abstract A captive study was performed with Greenland sledge dogs (Canis familiaris) fed a naturally organohalogen-contaminated diet (Greenland minke whale [Balaenoptera acutorostrata] blubber; exposed group) or a control diet (pork fat; control group). The catalytic activity of major xenobiotic-metabolizing phase I and II hepatic microsomal enzymes was assessed. Relative to control dogs, ethoxyresorufin- O -deethylase (EROD) activity in exposed dogs was twofold higher (p = 0.001). Testosterone hydroxylation yielded 6,- and 16,-hydroxy (OH) testosterone and androstenedione, with higher rates of production (23,27%; p , 0.03) in the exposed individuals. In the exposed dogs, epoxide hydrolase (EH) activity was 31% higher (p = 0.02) relative to the control dogs, whereas uridine diphosphoglucuronosyl transferase (UDPGT) activity was not different (p = 0.62). When the exposed and control dogs were combined, the summed (,) plasma concentrations of OH-polychlorinated biphenyl (PCB) congeners were predicted by plasma ,PCB concentrations and EROD activity (p , 0.04), whereas testosterone hydroxylase, EH, and UDPGT activities were not significant predictors of these concentrations. Consistent results were found for individual OH-PCB congeners and their theoretical precursor PCBs (e.g., 4-OH-CB-187 and CB-183, and 4-OH-CB-146 and CB-146) and for EROD activity. No association was found between ,OH,polybrominated diphenyl ether (PBDE) and ,PBDE plasma concentrations, or between potential precursor-metabolite pairs, and the enzyme activities. The present results suggest that liver microsomal EROD activity and plasma PCB concentrations have a greater (e.g., relative to EH activity) predictive power for the occurrence of plasma OH-PCB residues in sledge dogs. These results also suggest that plasma OH-PBDEs likely are not products of cytochrome P450-mediated transformation but, rather, are accumulated via the diet. [source]


    Susceptibility of the leaf-eating beetle, Galerucella calmariensis, a biological control agent for purple loosestrife (Lythrum salcaria), to three mosquito control larvicides

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2004
    T. Peter Lowe
    Abstract We evaluated the susceptibility of Galerucella calmariensis, a species used to control purple loosestrife (Lythrum salicaria), to three mosquito control larvicides. Larvae and adults were fed loosestrife cuttings dipped in Abate® (,375 g · L,1), Altosid® (,250 g · L,1), and Bacillus thuringiensis var israeliensis (Bti) (<110 g · L,1). Eggs on cuttings were dipped in the same concentrations. Pupae were immersed in Abate and Altosid solutions (,474.4 ,g · L,1 and ,1,169.2 ,g · L,1, respectively). Hatching success of eggs dipped in Abate (,3.75 g · L,1) was reduced significantly and survival was significantly lower among larvae and adults eating cuttings dipped in Abate (,0.17 g · L,1 and ,2.27 g · L,1, respectively). Hatching success of eggs dipped in Altosid (,2.52 g · L,1) was reduced significantly. With exposure to Altosid, larval survival to pupation and adult emergence was reduced significantly at concentrations of ,2.92 g · L,1 and ,0.63 g · L,1, respectively. Altosid (,0.23 g · L,1) also delayed the onset of pupation and adult emergence among larvae that survived to pupate. Larvae that survived with exposure to Altosid (,1.72 g · L,1) grew to 70% larger than those exposed to lower concentrations. Pupal survival was unaffected with exposure to Abate and Altosid and adult survival was unaffected with exposure to Altosid. Bacillus thuringiensis var israeliensis did not adversely affect any life stage of G. calmariensis. The mean Abate concentration on cuttings exposed to operational spraying was in the range that reduced egg hatchability and adult survival but was higher than concentrations that caused complete mortality of larvae. The mean Altosid concentration on cuttings exposed to operational spraying was in the range that reduced hatching success in eggs and delayed pupation and adult emergence of larvae. [source]


    Effect of copper on hatching and development of larvae of the estuarine crab Chasmagnathus granulata (Decapoda, Brachyura)

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2001
    Valeria Zapata
    Abstract Ovigerous females of the estuarine crab Chasmagnathus granulata were exposed to 0.05, 0.1, 0.5, and 3 mg/L of copper during the egg incubation period. Regarding egg loss, a higher effect was observed at higher copper concentrations: 80% of the females lost their eggs at 0.5 mg/L, whereas no hatching was seen in those exposed to 3 mg/L. A significant decrease was found in the number of hatched larvae in females exposed to 0.5 mg/L, as was a significant decrease in the duration of the incubation period. In addition, several morphological abnormalities were seen and observed. Hydropsy and atrophy of the dorsal spine, pleon, and maxillipeds occurred at the higher copper concentrations, as found in previous studies with other pollutants. Hyperpigmentation of the cephalothorax and pleon was the only abnormality observed at every concentration assayed. Hypopigmented eyes were also evident. This pathology showed that among all defects observed at 0.5 mg/L, hypopigmented eyes had the highest incidence and might be a specific response to copper. [source]


    Soil and plant diet exposure routes and toxicokinetics of lindane in a terrestrial isopod

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2000
    José Paulo Sousa
    Abstract In most studies dealing with effects of toxic substances in saprotrophic isopods, animals are exposed to the test substance through contaminated food. Because these animals can be in a close contact with the soil surface, the substrate, as an exposure pathway, should not be neglected. Here the authors analyze the toxicokinetic behavior of lindane (,-hexachlorocyclohexane [,-HCH]) in the isopod species Porcellionides pruinosus, comparing two exposure routes: food and two soil types (artificial Organisation for Economic Cooperation and Development [OECD] soil and a natural agricultural soil). In the feeding experiment, a strong decrease of ,-HCH concentration over time was observed on the food material, with the animals showing a broader range in chemical assimilation efficiency values (averaging 17.7% and ranging from 10 to 40%). The ,-HCH bioaccumulation results indicate that when animals incubated under both soil types reached a steady state, they displayed much higher body burdens (1,359.60 pg/animal on OECD soil and 1,085.30 pg/animal on natural soil) than those exposed to contaminated food (43.75 pg/animal). Kinetic models also revealed much lower assimilation and elimination rates in the food experiment (20.66 pg/d and 0.10 pg/d) than in both soil experiments (238.60 pg/d and 350.54 pg/d for the assimilation rate and 0.19 pg/d and 0.32 pg/d for the elimination rate). Differences in results between exposure routes are discussed according to equilibrium-partitioning theory and the enhanced relevance of the substrate exposure route is analyzed under future prospects on chemical toxicity testing using isopods. [source]


    Response of Daphnia magna to pulsed exposures of chlorpyrifos,

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000
    Rami B. Naddy
    Abstract Because aquatic organisms can be exposed to contaminants in an episodic manner, it is necessary to determine whether standard toxicity tests adequately simulate the toxicity of short-lived compounds, such as the organophosphate insecticide chlorpyrifos (CPF). We conducted experiments to evaluate the effect of binary combinations of concentration, duration, and interval of CPF exposures to Daphnia magna. Organisms were monitored for changes in survival and/or reproduction after pulsed exposure to CPF at 0.12, 0.25, 0.5, or 1.0 ,g/L. The exposure duration resulting in a 50% response in survival was 6.5 h at 1.0 ,g/L, 12.2 h at 0.5 ,g/L, and 48 h at 0.25 ,g/L. Daphnids exposed to two 12-h pulses of CPF at 0.5 ,g/L responded similarly (,85% mortality) regardless of the pulse interval (0, 3, 7, 14 d). However, daphnids were able to survive a 12-h exposure of CPF at 0.5 ,g/L if the exposure regime was separated into two 6-h pulses with a minimum interval of 3 d. Further experiments suggested that the interval studies may have been potentially confounded, because organisms exposed on day 3, 7, or 14 seemed more sensitive than those exposed as neonates. Additionally, no latent effects were measured for daphnids that survived the initial exposure. [source]


    In utero exposure to vigabatrin: No indication of visual field loss

    EPILEPSIA, Issue 2 2009
    Charlotte Lawthom
    Summary The purpose of the study was to determine whether in utero exposure to vigabatrin caused visual field loss. Three mothers with four children who had been exposed to vigabatrin in utero and who were subsequently formula fed were identified. All seven individuals underwent perimetry and imaging of the retinal nerve fiber layer (RNFL). All individuals yielded reliable outcomes to perimetry and RNFL images of acceptable quality. Two of the three mothers exhibited vigabatrin-attributed visual field loss and an abnormally attenuated RNFL. The third exhibited an upper left quadrantanopia, consistent with previous temporal lobe surgery, and a normal RNFL. All four children yielded normal visual fields and RNFL thicknesses. The presence of the normal findings for the children is reassuring and, if representative, suggests a lack of vigabatrin visual toxicity and therefore obviates the need for ophthalmological examination of those exposed to vigabatrin prenatally. [source]


    Effects of Potassium Concentration on Firing Patterns of Low-Calcium Epileptiform Activity in Anesthetized Rat Hippocampus: Inducing of Persistent Spike Activity

    EPILEPSIA, Issue 4 2006
    Zhouyan Feng
    Summary:,Purpose: It has been shown that a low-calcium high-potassium solution can generate ictal-like epileptiform activity in vitro and in vivo. Moreover, during status epileptiform activity, the concentration of [K+]o increases, and the concentration of [Ca2+]o decreases in brain tissue. Therefore we tested the hypothesis that long-lasting persistent spike activity, similar to one of the patterns of status epilepticus, could be generated by a high-potassium, low-calcium solution in the hippocampus in vivo. Methods: Artificial cerebrospinal fluid was perfused over the surface of the exposed left dorsal hippocampus of anesthetized rats. A stimulating electrode and a recording probe were placed in the CA1 region. Results: By elevating K+ concentration from 6 to 12 mM in the perfusate solution, the typical firing pattern of low-calcium ictal bursts was transformed into persistent spike activity in the CA1 region with synaptic transmission being suppressed by calcium chelator EGTA. The activity was characterized by double spikes repeated at a frequency ,4 Hz that could last for >1 h. The analysis of multiple unit activity showed that both elevating [K+]o and lowering [Ca2+]o decreased the inhibition period after the response of paired-pulse stimulation, indicating a suppression of the after-hyperpolarization (AHP) activity. Conclusions: These results suggest that persistent status epilepticus,like spike activity can be induced by nonsynaptic mechanisms when synaptic transmission is blocked. The unique double-spike pattern of this activity is presumably caused by higher K+ concentration augmenting the frequency of typical low-calcium nonsynaptic burst activity. [source]


    Teratogenic Effects of Antiepileptic Drugs: Use of an International Database on Malformations and Drug Exposure (MADRE)

    EPILEPSIA, Issue 11 2000
    Carla Arpino
    Summary: Purpose: The study goal was to assess teratogenic effects of antiepileptic drugs (AEDs) through the use of a surveillance system (MADRE) of infants with malformations. Methods: Information on all malformed infants (1990,1996) with maternal first-trimester drug exposure was collected by the International Clearinghouse for Birth Defects and Monitoring Systems (ICBDMS). Cases were defined as infants presenting with a specific malformation, and controls were defined as infants presenting with any other birth defect. Exposure was defined by the use of AEDs during the first trimester of pregnancy. The association of AEDs with malformations was then estimated by calculating the odds ratios with 95% confidence intervals and testing their homogeneity among registries. Results: Among 8005 cases of malformations, 299 infants were exposed in utero to AEDs. Of those exposed to monotherapy, 65 were exposed to phenobarbital, 10 to methylphenobarbital, 80 to valproic acid, 46 to carbamazepine, 24 to phenytoin, and 16 to other AEDs. Associations were found for spina bifida with valproic acid. Infants exposed to phenobarbital and to methylphenobarbital showed an increased risk of oral clefts. Cardiac malformations were found to be associated with phenobarbital, methylphenobarbital, valproic acid, and carbamazepine. Hypospadias was associated with valproic acid. Porencephaly and other specified anomalies of brain, anomalies of face, coarctation of aorta, and limb reduction defects were found to be associated with valproic acid. Conclusions: Using the MADRE system, we confirmed known teratogenic effects of AEDs. We also found increased risks for malformations that had never been reported associated with AEDs or for which the association was suggested by case reports. [source]


    Risk factors for epiploic foramen entrapment colic in a UK horse population: A prospective case-control study

    EQUINE VETERINARY JOURNAL, Issue 4 2008
    D. C. ARCHER
    Summary Reasons for performing study: Epiploic foramen entrapment (EFE) is a common cause of small intestinal strangulation in the horse and its epidemiology requires further investigation. Objectives: To identify horse- and management-level risk factors for EFE and to explore reasons for the apparent seasonality of this condition. Hypothesis: Horses exhibiting certain behaviours and those exposed to particular management practices that vary seasonally are at increased risk of EFE. Methods: A prospective unmatched, multicentre case-control study was conducted over 24 months in the UK. Data on 77 cases and 216 control horses were obtained from 9 collaborating clinics and logistic regression was used to identify associations between horse and management variables and the likelihood of EFE. Results: In a final multivariable model crib-biting/ windsucking behaviour was associated with the largest increase in likelihood of EFE. A history of colic in the previous 12 months, increased stabling in the previous 28 days and height of the horse also increased the likelihood of EFE. Horses with access to a mineral/salt lick, those easily frightened and horses not fed at the same time as others were at reduced risk of EFE. Conclusions: Horses exhibiting certain behaviours, those with a previous history of colic and horses of greater height appear to be at inherently greater risk of EFE. The increase in likelihood of EFE with increased duration of stabling may explain the apparent seasonality of this condition. Potential relevance: These findings assist identification of horses at high-risk of EFE and provide information on management strategies that may reduce this risk. If the observed associations are causal, avoiding sudden increases in duration of stabling, not feeding horses in the same group at the same time and providing a mineral/salt lick may reduce the likelihood of EFE. The risk factors identified in this study provide important clues to the aetiology of EFE. [source]


    Has Finance Made the World Riskier?

    EUROPEAN FINANCIAL MANAGEMENT, Issue 4 2006
    Raghuram G. Rajan
    G20; G21; G22 Abstract Developments in the financial sector have led to an expansion in its ability to spread risks. The increase in the risk bearing capacity of economies, as well as in actual risk taking, has led to a range of financial transactions that hitherto were not possible, and has created much greater access to finance for firms and households. On net, this has made the world much better off. Concurrently, however, we have also seen the emergence of a whole range of intermediaries, whose size and appetite for risk may expand over the cycle. Not only can these intermediaries accentuate real fluctuations, they can also leave themselves exposed to certain small probability risks that their own collective behaviour makes more likely. As a result, under some conditions, economies may be more exposed to financial-sector-induced turmoil than in the past. The paper discusses the implications for monetary policy and prudential supervision. In particular, it suggests market-friendly policies that would reduce the incentive of intermediary managers to take excessive risk. [source]


    Olfactory deficits in mice overexpressing human wildtype ,-synuclein

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2008
    Sheila M. Fleming
    Abstract Accumulation of ,-synuclein in neurons of the central and peripheral nervous system is a hallmark of sporadic Parkinson's disease (PD) and mutations that increase ,-synuclein levels cause familial PD. Transgenic mice overexpressing ,-synuclein under the Thy1 promoter (Thy1-aSyn) have high levels of ,-synuclein expression throughout the brain but no loss of nigrostriatal dopamine neurons up to 8 months, suggesting that they may be useful to model pre-clinical stages of PD. Olfactory dysfunction often precedes the onset of the cardinal motor symptoms of PD by several years and includes deficits in odor detection, discrimination and identification. In the present study, we measured olfactory function in 3- and 9-month-old male Thy1-aSyn mice with a buried pellet test based on latency to find an exposed or hidden odorant, a block test based on exposure to self and non-self odors, and a habituation/dishabituation test based on exposure to non-social odors. In a separate group of mice, ,-synuclein immunoreactivity was assessed in the olfactory bulb. Compared with wildtype littermates, Thy1-aSyn mice could still detect and habituate to odors but showed olfactory impairments in aspects of all three testing paradigms. Thy1-aSyn mice also displayed proteinase K-resistant ,-synuclein inclusions throughout the olfactory bulb. These data indicate that overexpression of ,-synuclein is sufficient to cause olfactory deficits in mice similar to that observed in patients with PD. Furthermore, the buried pellet and block tests provided sufficient power for the detection of a 50% drug effect, indicating their usefulness for testing novel neuroprotective therapies. [source]


    Corrosion of some selected ceramic alloys used in fixed partial dentures and their postsolder joints in a synthetic neutral saliva

    EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2009
    Pascal De March
    The electrochemical behavior of several alloys used in the frameworks of fixed partial dentures and their corresponding postsolders was studied in artificial saliva as a function of chemical composition. Open circuit potentials and polarization resistances were measured. The general electrochemical behaviors between the cathodic domain and the oxidation of solvent were characterized using cyclic polarization. The possible galvanic corrosion of coupled parent and postsolder alloys was also studied. The polarization resistances were high or very high. During immersion, the noblest alloys stayed in the immunity domains of their base elements, whereas Ni,Cr alloys were quickly passivated. The oxidation of the noble elements occurred only when the alloys were exposed to very high potentials solely achievable by artificial means. However, problems of galvanic corrosion may occur between an alloy and its postsolder joint if they are both exposed to saliva. Such corrosion may lead to a weakening of the framework. The parent alloy was often potentially affected by such corrosion but with low exchange currents. [source]


    Perspective taking and prejudice reduction: the mediational role of empathy arousal and situational attributions

    EUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 4 2003
    Theresa K. Vescio
    This research was designed to examine whether perspective taking promotes improved intergroup attitudes regardless of the extent that stereotypic perceptions of outgroups are endorsed, as well as examining the mechanisms (attributional or empathy related) by which perspective taking motivates improved intergroup attitudes. Participants were presented with an interview segment where an African American interviewee discussed the difficulties experienced as a result of his membership in a negatively stereotyped group. Materials were presented in a 2 (perspective taking: other focused or objective focused),×,2 (target stereotypicality: confirming or disconfirming) between participants design. Findings revealed that the manipulation of target stereotypicality influenced subsequent stereotype endorsement; those exposed to a stereotype confirming target later endorsed more stereotypic perceptions of African Americans than did those exposed to a stereotype disconfirming target. However, perspective taking promoted improved intergroup attitudes irrespective of stereotypicality; those encouraged to adopt the perspective of the target later reported more favourable intergroup attitudes than did those who remained detached and objective listeners. Whereas empathy partially mediated the relation between perspective taking and intergroup attitudes, situational attributions were a stronger and more reliable mediator. Copyright © 2003 John Wiley & Sons, Ltd. [source]


    Changes in Cerebral Blood Flow During and After 48 H of Both Isocapnic and Poikilocapnic Hypoxia in Humans

    EXPERIMENTAL PHYSIOLOGY, Issue 5 2002
    Marc J. Poulin
    During acclimatization to the hypoxia of altitude, the cerebral circulation is exposed to arterial hypoxia and hypocapnia, two stimuli with opposing influences on cerebral blood flow (CBF). In order to understand the resultant changes in CBF, this study examined the responses of CBF during a period of constant mild hypoxia both with and without concomitant regulation of arterial PCO2. Nine subjects were each exposed to two protocols in a purpose-built chamber: (1) 48 h of isocapnic hypoxia (Protocol I), where end-tidal PO2 (PET,O2) was held at 60 Torr and end-tidal PCO2 (PET,CO2) at the subject's resting value prior to experimentation; and (2) 48 h of poikilocapnic hypoxia (Protocol P), where PET,O2 was held at 60 Torr and PET,CO2 was uncontrolled. Transcranial Doppler ultrasound was used to assess CBF. At 24 h intervals during and after the hypoxic exposure CBF was measured and the sensitivity of CBF to acute variations in PO2 and PCO2 was determined. During Protocol P, PET,CO2 decreased by 13% (P < 0.001) and CBF decreased by 6% (P < 0.05), whereas during Protocol I, PET,CO2 and CBF remained unchanged. The sensitivity of CBF to acute variations in PO2 and PCO2 increased by 103% (P < 0.001) and 28% (P < 0.01), respectively, over the 48 h period of hypoxia. These changes did not differ between protocols. In conclusion, CBF decreases during mild poikilocapnic hypoxia, indicating that there is a predominant effect on CBF of the associated arterial hypocapnia. This fall occurs despite increases in the sensitivity of CBF to acute variations in PO2/PCO2 arising directly from the hypoxic exposure. [source]


    THE CAUSES OF GIRLS' DELINQUENCY AND THEIR PROGRAM IMPLICATIONS

    FAMILY COURT REVIEW, Issue 3 2007
    Margaret A. Zahn
    This article summarizes some of the literature reviewed by the Girls Study Group, which is a federally funded project aimed at assessing the causes of girls' delinquency as well as evaluating programs to address it. The literature reveals that a number of factors such as family dysfunction, involvement with antisocial peers, and living in disadvantaged neighborhoods are correlated with delinquency for both boys and girls. Some factors, however, are gender sensitive, meaning that either girls are more exposed to a given risk factor than boys or react somewhat differently to a given risk factor. Girls have higher rates of exposure to sexual assault, which is associated with delinquency and, although more research is needed, they are more affected by the impacts of early puberty, when it is coupled with harsh parenting and disadvantaged neighborhoods. This article discusses some implications of the research on correlates of delinquency for programming for girls and makes recommendations for program selection. [source]